Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • NCERT
  • If A is square matrix such that A = A, then (I + A)3 - 7 A is equal to (A) A (B) I - A (C) I (D) 3A

Q15.    If A is square matrix such that A^{2}=A, then (I + A)^3 - 7 A is equal to

            (A) A
            (B) I – A
            (C) I
            (D) 3A

Answers (1)

best_answer

A is square matrix such that A^{2}=A

(I + A)^3 - 7 A 

=I^{3}+A^{3}+3I^{2}A+3IA^{2}-7A

=I+A^{2}.A+3A+3A^{2}-7A

=I+A.A+3A+3A-7A             (Replace A^{2}  by A)

=I+A^{2}+6A-7A

=I+A-A

=I

Hence, we have  (I + A)^3 - 7 A=I

Option C is correct.

Posted by

seema garhwal

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads

Similar Questions

Trending Articles/News

anam-khan

Board Exam Result 2025 Live: UK Board 10th, 12th results tomorrow; AP SSC, TS Inter, UP, CBSE updates
anam-khan

When will CBSE Class 12 results 2025 be declared? Last two years' trends
anam-khan

CBSE Class 10, 12 board exams 2025 from April 7 to 11 for sports students

Latest Question